This invention relates to a discharge and transfer system for handling an endmost one of a series of advancing items, and more particularly to a discharge and transfer system for supplying groups of sheets from an interfolder to a packaging machine in which the groups of sheets are banded or wrapped.
Interfolded sheets, such as paper towels or the like, are typically interfolded together in a nip defined between a pair of folding rolls. The interfolded sheets are discharged from the folding rolls in a vertical downward direction. The sheets are separated into groups or “logs” of interfolded sheets that are stacked together, and each log of sheets is supplied to a packaging machine that applies a wrapper or band about the log. The wrapped or banded log is then supplied to a cutting device, commonly known as a log saw, in which the log is cut into a series of individual packs in preparation for shipment.
Several systems are known for handling the sheets that are discharged from the folding rolls. In one such prior art system, such as is disclosed in Couturier U.S. Pat. No. 4,770,402 issued Sep. 13, 1988, the sheets are discharged from the nip between the folding rolls onto a vertically movable platform. The sheets discharged onto the platform are counted, and fingers or the like are inserted into the stack of sheets at a predetermined count in order to support the sheets discharged from the folding rolls while the stack supported on the platform is separated from the sheets supported by the fingers, by lowering the platform. The sheets are then moved off the platform by a conveyor or the like for subsequent supply to a packaging machine in which the stack of sheets is banded or wrapped. The platform is then moved upwardly to support the stack supported by the fingers, and the fingers are retracted in preparation for engagement within the stack when the sheet count reaches a predetermined number.
Another system is disclosed in copending application Ser. No. 09/565,729 filed May 5, 2000, the disclosure of which is hereby incorporated by reference. The '729 application discloses a system in which the sheets discharged from the nip between the folding rolls are guided from vertical movement at the discharge of the folding rolls to horizontal movement on a table. The table includes a belt arrangement having an upper run that underlies the sheets, and which is operable to advance the sheets on the table in a horizontal direction away from the discharge area of the folding rolls. The sheets are separated into individual groups or logs of sheets in the interfolding process, such as is disclosed in White U.S. Pat. No. 6,165,116, the disclosure of which is hereby incorporated by reference. In this manner, the individual groups or logs of sheets are advanced on the table by the upper run of the belt arrangement toward a clamping mechanism located at a downstream area of the table. The endmost group of sheets is separated from the adjacent groups of sheets at the downstream area of the table via the clamping mechanism, which engages an end of the endmost group of sheets and is then moved laterally so as to apply a lateral force to the endmost group of sheets to move the endmost group of sheets laterally in a lengthwise direction. In this system, the sheets are oriented vertically upon discharge and are subsequently turned so as to be oriented horizontally, in preparation for processing through the packaging or wrapping apparatus.
Separating the groups of sheets in the interfolder, as disclosed in the '116 patent, enables the groups of sheets to be efficiently handled upon discharge from the interfolder, and eliminates the need to separate the sheets after discharge from the interfolder as is disclosed in the '402 patent. This feature is exploited by the system disclosed in the copending '729 application, in that the endmost group of sheets can be discharged laterally in a lengthwise direction relative to the adjacent group of sheets without the need to create a separation between the endmost group of sheets and the remainder of the sheets. However, discharging the endmost group of sheets as disclosed in the copending '729 application requires that the group of sheets be rotated or “flipped” in preparation for subsequent processing through the packaging or wrapping apparatus, in order for the group of sheets to be self-supporting during advancement through the packaging or wrapping apparatus.
It is an object of the present invention to provide a discharge and transfer system for a stack or group of interfolded sheets, which eliminates the need to rotate, the sheets after discharge and prior to supply of the sheets to a packaging or wrapping apparatus. It is another object of the invention to provide such a discharge and transfer system which minimizes the number of handling steps between discharge of the sheets from the interfolder and supply of the sheets to the packaging or wrapping apparatus. It is a further object of the invention to provide such a system which takes advantage of the separation between adjacent groups of sheets created in the interfolding process. A still further object of the invention is to provide such a system which is relatively simple in its components and construction, yet which provides an efficient and effective arrangement for supplying sheets from an interfolder to a packaging or wrapping apparatus.
In accordance with one aspect of the invention, a transfer system for interfolded sheets includes an advancing arrangement for advancing the groups of separated sheets in a forward direction, a guide arrangement which directs the groups of sheets so as to move the groups of sheets in an upward direction to a transfer area, and a discharge arrangement for engaging the uppermost group of sheets at the transfer area and moving the uppermost group of sheets lengthwise to separate the uppermost group of sheets from the next adjacent group of sheets. The groups of sheets are preferably discharged in adjacent separated groups of sheets from the interfolder, and the advancing arrangement is operable to move the groups of sheets away from the interfolder in a forward direction that is generally perpendicular to a longitudinal axis defined by each group of sheets. The guide arrangement is configured to position the sheets such that the downstream or uppermost group of sheets at the transfer area is supported by a series of upstream groups of sheets located below the downstream or uppermost group of sheets.
The groups of sheets may be discharged from the interfolder in a downward direction, and the sheets are subsequently moved in a generally horizontal direction by an advancing belt arrangement on a support surface such as a table, in a manner as is known. The guide arrangement of the present invention includes an upstream portion that functions to engage the sheets during advancement, and the guide arrangement is configured to alter the direction of movement of the groups of sheets from the generally horizontal direction to a generally vertical direction at the transfer area. In one form, the guide arrangement comprises stationary curved guide wall structure that engages the groups of sheets downstream of the advancing belt arrangement and alters the direction of movement of the groups of sheets from the generally horizontal direction to the generally vertical direction. The advancing belt arrangement is operable to move the groups of sheets along the stationary guide wall by pushing the sheets along the guide wall by engagement with the upstream groups of sheets.
The discharge arrangement may be in the form of a pair of spaced apart movable members located at the transfer area, which are configured to engage the uppermost group of sheets at the transfer area and to move the uppermost group of sheets lengthwise along the longitudinal axis of the uppermost group of sheets. The separation between the uppermost group of sheets and the next adjacent group of sheets enables the uppermost group of sheets to be moved lengthwise relative to the next adjacent group of sheets. The pair of movable members may be in the form of a pair of discharge belts that define facing engagement runs between which the uppermost group of sheets is located when the uppermost group of sheets is at the transfer area, and operation of the discharge belts functions to propel the uppermost group of sheets in a lengthwise direction.
In accordance with another aspect of the invention, a downstream processing apparatus, such as a packaging or wrapping apparatus, is located adjacent the transfer area, and includes an inlet area that is adapted to receive a group of sheets. The downstream processing apparatus is configured to move the group of sheets in a lengthwise direction for subsequent processing, such as application of packaging or wrapping material about the group of sheets as the group of sheets is moved through the packaging or wrapping apparatus. The inlet area of the downstream processing apparatus is located adjacent and in alignment with the transfer area, such that lengthwise movement of the group of sheets from the transfer area by operation of the discharge belts functions to move the uppermost stack of sheets into the inlet area of the downstream processing apparatus.
The invention contemplates a discharge and transfer system as summarized above, as well as a method of transferring a group of sheets, substantially in accordance with the foregoing summary.
Various other features, objects and advantages of the invention will be made apparent from the following description taken together with the drawings.